In the fabrication of semiconductor devices, temperature treatment of the semiconductor substrate (herein after referred to as a wafer) is a necessary process step. Rapid thermal processing is often used during the processing of semiconductor devices for annealing materials, curing layers and activating compounds to name a few, and performed in a rapid thermal process tool. While effective in heating the wafer, the radiation pattern from the heating elements of the tool causes temperature variations in the material of the wafer. Temperature variations in the wafer cause, for example, material phase differences, doping nonuniformities, and stress gradients which are detrimental to the fabrication process.
The temperature variations are reduced by providing a susceptor carrying the wafer. A conventional susceptor is a container having a flat bottom upon which the wafer is placed. A lid is used to reduce convection currents near the wafer so the wafer is heated by transfer of heat from the bottom of the susceptor. The use of a susceptor minimizes temperature variations in the substrate. However, in very sensitive materials, temperature variations result from mechanical contact between the susceptor and the wafer, with flatness of the susceptor being critical to insure good mechanical contact which results in uniform thermal distribution. Any unevenness in the susceptor or the wafer will result in non-uniform thermal contact and temperature variation.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide an new improved rapid thermal processing susceptor.
Another object of the present invention is to provide a rapid thermal processing susceptor which improves thermal uniformity and reproducibility of the temperature in wafers.
And another object of the present invention is to provide a rapid thermal processing susceptor which minimizes the thermal contact area between susceptor and wafer.
Still another object of the present invention is to provide a rapid thermal processing susceptor which minimizes backside contamination and cross contamination of wafers.
Yet another object of the present invention is to provide a rapid thermal processing susceptor in which the dimensions can be manipulated in specific applications to heat the surfaces of a wafer differently.
And still another object of the present invention is to provide a rapid thermal processing susceptor which improves the gas flow within the susceptor.
A further object of the present invention is to provide a rapid thermal processing susceptor which can be employed with an automated rapid thermal processing tool.